Elongated element to be driven into the ground together with a shoe

ABSTRACT

An elongated element, such as a foundation pile or a tube for casting a concrete foundation pile in situ, adapted to be driven in the ground, in particular by vibration, together with a shoe, and comprising at least one supply pipe connected with the outer wall of the element, extending in the longitudinal direction of the same, terminating near the lower end of the element, and connectable at its top, through a supply valve, to a source of a pressure medium, in particular water under pressure. Each supply pipe, respectively, is provided at its lower end with means preventing a penetration of earth into the supply pipe substantially completely when the supply valve is closed, but allowing a discharge of the pressure medium from the supply pipe when the supply valve is open.

United States Patent 2.555.359 6/1951 Montague. 2,600,150 6/1952Abendroth 2,662,603 12/1953 Jones. 175/314 3,166,132 1/1965 Lenahanetal. 175/314 X Primary Examiner- David J. Williamowski AssistantExaminerDavid H. Corbin [21 Appl. No. [22] Filed Dec. 19, 1969 [45]Patented Dec. 28, 1971 [73] Assignee N.V. tot Aanneming van Wei-kenvoorheen i rzg zi gzs Attorney-"Waters, Roditi, Schwartz & Nissen [32]Priorities Dec. 20, 1968 [3 3] Netherlands [31] 6818364;

July 15, 1969, Netherlands, No. 6910827 ABSTRACT: An elongated element.such as a foundation pile 5 ELONGATED ELEMENT o BE DRIVEN 01 a tube forcasting a 001161516 foundation in situ, THE GROUND TOGETHER WITH A SHOEadapted to be driven in the ground, in particular by vibration, 3 Claims3 Drawing Figs together with a shoe. and comprising at least one supplypipe connected with the outer wall ofthe element. extending in the CLlongitudinal direction of the same. terminating near the lower end ofthe element, and connectable at its top, through a supply valve, to asource of a pressure medium, in particular water under pressure. Eachsupply pipe, respectively, is provided at its lower end with meanspreventing a penetration of earth into the supply pipe substantiallycompletely when the supply valve is closed, but allowing a discharge ofthe pressure medium from the supply pipe when the supply valve is open.

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ELONGATED ELEMENT TO BE DRIVEN INTO THE GROUND TOGETHER WITH A SHOEBACKGROUND OF THE INVENTION When an elongated element provided with ashoe, such as a foundation pile or a tube for casting a concretefoundation pile in situ, is driven into the ground, for instance byvibration, the desired depth can often only be reached if a sufficienthydraulic overpressure is present or may be artificially generated.

For the latter purpose, it is known to provide an element of theabove-mentioned kind with at least one supply pipe, connected with theouter wall of the element and extending in the longitudinal direction ofthe same. This supply pipe terminates near the bottom of the element,and is connectable at its top through a supply valve to a source of apressure medium, in particular water under pressure.

This pressure medium serves to achieve an artificial reduction of thecontact pressure of the ground particles underneath the shoe.Furthermore, if the pressure medium is a liquid, such as water, theliquid ascending around the element will carry away the groundparticles, whereby space is obtained for the volume occupied by theelement. However, since the pressure medium flows away in this case, itmust be supplied in large quantities in order to increase the pressurein the ground pores and to reduce the contact pressure of the groundparticles to such an extent that the element may be driven further intothe ground. In addition, the use of a liquid pressure medium involves aconsiderable spoilage of the building site by the liquid dischargedalong the element, and in particular by the deposition of the groundparticles carried along with this liquid.

Moreover, with the known elements, it is not possible to interrupt thesupply of the pressure medium periodically during the driving process,because the earth would penetrate into the supply pipes during suchinterruptions, whereby the pipes would be clogged and a further supplyof the pressure medium would be rendered impossible. On the other hand,the ground structure is frequently of such a nature that it is not onlyunnecessary, but even harmful to supply the pressure medium during theentire driving period, because in soft ground layers, and especially inclay and sludge layers, the supply of a liquid pressure medium has thedisadvantage that too much ground is carried away, and the groundsurrounding the element is heavily disturbed, so that the element is nolonger entirely enclosed by the ground.

SUMMARY OF THE INVENTION The invention has the object to provide anelement of the above-mentioned kind whereby the said disadvantages areeffectively removed.

According to the invention, each supply pipe, respectively, is providedat its lower end with means preventing a penetration of ground into thesupply pipe substantially completely when the supply valve is closed,but allowing a discharge of the pressure medium from the supply pipewhen the supply valve is open.

The invention also comprises a method of driving said element into theground, in particular by vibration.

According to this method, the supply valve is periodically closed duringthe driving process.

In a preferred embodiment of the method according to the invention, thesupply valve is closed at least during the initial period. Since nopressure medium is supplied during the initial period of the drivingprocess, the element is tightly enclosed by the ground, and the diameterof the region in which the ground displaced by the element isincorporated by densification is considerably increased. A leakage ofthe pressure medium supplied during the remaining portion of the drivingprocess is effectively prevented in this manner, so that the quantity ofthe pressure medium introduced into the ground is accurately defined,and the required reduction of the contact pressure of the groundparticles may be obtained with a minimum consumption of the pressuremedium. If the pressure medium is a liquid, the spoilage of the buildingsite is also effectively reduced.

BRIEF DESCRIPTION OF THE DRAWING dicated.

FIG. 3 is a longitudinal section of the lower end of a modification ofthe supply pipe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a portion of atube 1 which is adapted to be driven into the ground, in particular byvibration, together with a loose shoe 2. The tube 1 serves as a mouldfor the casting in situ of a concrete foundation pile, and is afterwardsremoved.

The tube 1 is provided on its outside with a plurality of supply pipes 3for a pressure medium, in general water under pressure; these supplypipes are spaced at equal distances along the periphery of tube 1. Threesupply pipes are shown in the drawings. The supply pipes 3 are attached,for instance by welding, to the outer wall of tube 1. As appears fromFIG. I, the lower ends of the supply pipes 3 may be offset to theoutside, at their top, the supply pipes 3 are connected, through asupply valve, to a source ofthe pressure medium.

At its lower end, each of the supply pipes 3 carries an outlet nozzle 4,screwed into a nipple 5; the nipple 5 is screwed into the lower end ofthe supply pipe. The outlet nozzle 4 has an outlet channel 6 with areduced diameter, whose lower part 7 terminates immediately underneaththe loose shoe 2, and is downwardly inclined toward the axis of tube 1.

A back pressure valve 8 is arranged above the outlet nozzle 4. The valve8 comprises a spring 9 supported by the outlet nozzle 4, and exerting anupward force, through the intermediary of a pressure member 10, on aspherical valve body 11, whereby the latter is pressed against a valveseat 12 provided in the top face of the nipple 5.

When the supply valve at the top of the supply pipe 3 is open, the valvebody 11 is lowered by the overpressure of the medium, which may amountto 10 atm., so that the pressure medium is discharged through the outletnozzle 4. As soon as the supply of the pressure medium is interrupted,the back pressure valve 8 is immediately closed, so that a penetrationof earth into the supply pipe is substantially completely prevented.

As appears from FIG. 2, the peripheral edge of the loose shoe 2 isprovided with recesses 13 partially enclosing the outlet nozzles 4.

FIG. 3 shows a modification of the supply pipe 3. A sleeve 14, made of aporous material, such as sintered bronze, rests against a shoulder 15formed in the supply pipe 3, and is retained by a plug 16 screwed intothe lower end of the supply pipe. The interior of the sleeve 14 is inopen communication with the interior of the supply pipe 3. Outside thesleeve 14, an outlet channel 17 has been formed in the wall of thesupply pipe 3. The channel 17 terminates immediately underneath theloose shoe 2, and is downwardly inclined toward the axis of the tube 1.

The porous sleeve 14 passes the pressure medium, but prevents the groundfrom penetrating into the supply pipe. This embodiment is possiblebecause the force of the discharged jet of the pressure medium does notplay any significant part.

The invention makes it possible to interrupt the supply of the pressuremedium periodically during the driving process without any danger of aclogging of the supply pipes by the surrounding earth.

Preferably, the supply of the pressure medium is interrupted during theinitial stage of the driving process, so that the tube 1 may be tightlyenclosed by the ground, and any leakage of the pressure medium duringthe remaining portion of the driving process is effectively prevented.Thus, the required reduction of the contact pressure of the groundparticles is obtained with a minimum consumption of the pressure medium,and a spoilage of the building site with overflowing water is prevented.

Furthermore, the supply of the pressure medium may be stoppedimmediately before the required depth is reached, so that a sufficientdensification of the ground underneath the shoe 2 may be obtained, whichis necessary for adequate carrying of the final foundation pile.

The invention is not restricted to the embodiments shown in thedrawings, which may be modified in various ways within the scope of theinvention. For instance, the invention may also be applied to aprefabricated foundation pile.

What is claimed is:

1. In combination, an elongated foundation pile element having a shoe atthe lower end thereof, for casting a concrete foundation pile in situand adapted to be driven into the ground by vibration; and at least onesupply pipe connected to the exterior of said element and beingcoextensive therewith along its longitudinal length, said supply pipeterminating adjacent the lower end of said element, said supply pipebeing connected at its upper end to a source of liquid pressure mediumadapted to supply said pressure medium to said supply pipe in anintermittent manner during the driving of said element, a pressuremedium outlet nozzle in said supply pipe at the lower end thereof, saidnozzle comprising an axial channel and a liquid outlet channel extendingobliquely from said axial channel and being directed toward thelongitudinal axis of said element and having an outlet orificeterminating immediately adjacent and below said shoe, and means in saidsupply pipe in the lower region thereof for permitting a discharge ofsaid pressure medium from said supply pipe through said nozzle duringperiods of supply of liquid pressure medium to said pipe, and preventingpenetration of ground particles into said supply pipe upon cessation ofliquid pressure medium flow through said pipe.

2. The combination as claimed in claim 1, wherein said lastmentionedmeans comprises a ball check valve, vale seat means in said supply pipe,and resilient spring means biassing said valve toward said valve seatmeans into normally valveclosed position, said valve being adapted toopen in response to liquid pressure medium flow through said supplypipe, and close upon cessation of pressure medium flow so as to preventground particles entering said supply pipe.

3. The combination as claimed in claim 1, wherein said lastmentionedmeans comprises a sintered bronze, porous sleeve member interposedbetween the interior of said supply pipe and said outlet channel, saidliquid pressure medium being conveyed through said sleeve member towardsaid channel during periods of pressure medium flow, and preventingentry of ground particles into said supply pipe upon cessation of liquidpressure medium flow through said pipe.

1. In combination, an elongated foundation pile element having a shoe atthe lower end thereof, for casting a concrete foundation pile in situand adapted to be driven into the ground by vibration; and at least onesupply pipe connected to the exterior of said element and beingcoextensive therewith along its longitudinal length, said supply pipeterminating adjacent the lower end of said element, said supply pipebeing connected at its upper end to a source of liquid pressure mediumadapted to supply said pressure medium to said supply pipe in anintermittent manner during the driving of said element, a pressuremedium outlet nozzle in said supply pipe at the lower end thereof, saidnozzle comprising an axial channel and a liquid outlet channel extendingobliquely from said axial channel and being directed toward thelongitudinal axis of said element and having an outlet orificeterminating immediately adjacent and below said shoe, and means in saidsupply pipe in the lower region thereof for permitting a discharge ofsaid pressure medium from said supply pipe through said nozzle duringperiods of supply of liquid pressure medium to said pipe, and preventingpenetration of ground particles into said supply pipe upon cessation ofliquid pressure medium flow through said pipe.
 2. The combination asclaimed in claim 1, wherein said last-mentioned means comprises a ballcheck valve, vale seat means in said supply pipe, and resilient springmeans biassing said valve toward said valve seat means into normallyvalve-closed position, said valve being adapted to open in response toliquid pressure medium flow through said supply pipe, and close uponcessation of pressure medium flow so as to prevent ground particlesentering said supply pipe.
 3. The combination as claimed in claim 1,wherein said last-mentioneD means comprises a sintered bronze, poroussleeve member interposed between the interior of said supply pipe andsaid outlet channel, said liquid pressure medium being conveyed throughsaid sleeve member toward said channel during periods of pressure mediumflow, and preventing entry of ground particles into said supply pipeupon cessation of liquid pressure medium flow through said pipe.